在 numpy 数组中平滑具有粗糙边界的二维轮廓

Question

I have a contour that is represented in a numpy array in such a way that the boundary points have 1 and the rest are 0. An example image is shown below. How could I smooth this contour?

I am trying the get a contour that is smoother than the one in the image right now

Answer 1

You can use active_contour to match a spline with a set number of points to your contour. If you lower the number of points you get a smoother contour.

Answer 2

You can use morphological transformations such as erosion and dilation. OpenCV has a nice tutorial here: https://docs.opencv.org/master/d9/d61/tutorial_py_morphological_ops.html

Answer 3

As @Mad Physicist says you can use morphological techniques I recommend using Opening (Dilation and erosion) followed by a dilation as follows:

import cv2
import numpy as np

img = cv2.imread('img.png',0)
kernel  = cv2.getStructuringElement(cv2.MORPH_ELLIPSE,(11,11))
      

opening = cv2.morphologyEx(img, cv2.MORPH_OPEN, kernel,iterations= 5)

opening = cv2.dilate(opening,kernel,iterations = 1)

img_window = np.hstack((img,opening))

cv2.imshow("image",img_window)

cv2.waitKey(0)

cv2.destroyAllWindows()

results: